In this episode of IM Basics, Dr. Eric and Dr. Tark continue their shock series with a practical discussion of hypovolemic and hemorrhagic shock, focusing on bedside recognition, diagnostic strategies, and early management.

The episode begins with a review of shock pathophysiology, emphasizing reduced preload as the primary driver of both conditions. Loss of intravascular volume leads to decreased cardiac output and impaired end-organ perfusion, triggering a compensatory sympathetic response with vasoconstriction, tachycardia, and narrow pulse pressures.

The hosts highlight that hypotension is often a late finding. Earlier signs include tachycardia, cool extremities, delayed capillary refill, and altered mental status. The shock index (heart rate divided by systolic blood pressure) is introduced as a useful early marker, with values above 0.7 suggesting instability and values ≥1.0 indicating severe shock.

A major focus is on identifying the source of volume loss or bleeding. Hemorrhage is framed simply: patients bleed externally or into limited internal compartments such as the chest, abdomen, pelvis, or thighs. Point-of-care ultrasound (FAST exam) is emphasized as a first-line tool in unstable patients, with CT angiography and interventional radiology considered when patients can be stabilized.

For hypovolemic shock, common causes discussed include gastrointestinal losses, poor oral intake, diuretic use, osmotic diuresis (e.g., DKA), and third spacing from conditions like pancreatitis or advanced liver disease.

Management centers on early resuscitation, distinguishing fluid replacement for hypovolemia from early blood product administration for hemorrhagic shock. The hosts caution against excessive crystalloid use due to dilutional coagulopathy and DIC risk, and review massive transfusion principles, including balanced ratios of blood products and emerging data on whole-blood transfusion.

The episode also covers fluid selection, favoring balanced crystalloids such as lactated Ringer’s, and discusses vasopressors as adjuncts when hypotension persists despite adequate resuscitation or while definitive hemorrhage control is pending.

Key pitfalls are reviewed, including reliance on a normal initial hemoglobin, failure to reassess volume status, fluid overload causing pulmonary edema, and delays in specialist involvement. The episode closes with an emphasis on early communication with surgical, interventional, GI, and critical care teams to improve outcomes.

*Episode reviewed by Dr. Teshome Hailemichael, Core Faculty - Internal Medicine

Key References

1. Guyton AC, Hall JE. Textbook of Medical Physiology. 14th ed. Elsevier; 2021.
2. Advanced Trauma Life Support (ATLS®): Student Course Manual. 10th ed. American College of Surgeons; 2018.
3. Cannon JW. Hemorrhagic Shock. N Engl J Med. 2018;378:370–379. – Comprehensive review of hemorrhagic shock pathophysiology and resuscitation strategies.
4. Rhodes A, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock 2021. Intensive Care Med. 2021.
5. Holcomb JB, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 ratio and mortality in patients with severe trauma. JAMA. 2015;313(5):471–482.
6. Semler MW, et al. Balanced Crystalloids versus Saline in Critically Ill Adults. N Engl J Med. 2018;378:829–839..